* {
  margin: 0;
  padding: 0;
}

button {
  outline: none;
}

.bar {
  display: flex;
}

h2 {
  line-height: 50px;
}

button {
  border: 1px solid #ddd;
  background: #eee;
  cursor: pointer;
  font-size: 16px;
  height: 50px;
  width: 150px
}

button:hover {
  background: #ddd;
}

.box {
  width: 500px;
  height: 300px;
  margin: 100px;
  color: white;
  background: #333;
}

.fu {
  width: 500px;
  height: 300px;
  background: #333;
  margin: 100px;
}

.zi {
  width: 100px;
  height: 100px;
  margin: 100px;
  background: blue;
}

.main {
  width: 600px;
  background: #ddd;
  height: 700px;
}

.side {
  float: left;
  height: 500px;
  width: 200px;
  background: #ccc;
}

.nav {
  margin-top: 50px;
  background: #333;
  margin-bottom: 500px;
}

.nav li {
  float: left;
  width: 100px;
  height: 50px;
  color: #ddd;
  line-height: 50px;
  text-align: center;
}


